About Home Tiles and Tiling – Part Two
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| Home Tiles and Tiling |
The Ways to Set Out Ceramic Tiles
What I'm going to do here is give you some guidelines for the setting out process when laying tile. Keep in mind that these are only guidelines and that your situation or job may have some different quirks where my advice won't work.
A general bit of advice when cutting tiles is to never cut them less than half of the original. This is mostly for looks and it's hard to tell when the cut pieces are along walls. In other words, if a wall is 5mm out of plumb or square, the eye can't tell if the tile is cut at around half. However, if a tile is cut smaller like around 15-20mm then the naked eye will be able to detect the out of plumb wall.
House Floor Planning for Ceramic Tiles
When making a plan for the house floor, you should consider the following:
- Longest run
- Centre line
- Next longest run
- Lines at right angles
By longest run I mean the longest length of continuous tiles. This will typically be in an area such as a hallway. When the longest run is laid right, everything else will come out right too. This is also where the centre line is set and it should be exactly parallel to the wall.
The next run is the one that intersects the longest. it's usually laid out at a right angle to the longest run across a dining or livingroom. Here again, it should be parallel to the wall it runs along.
The next step in planning for laying tile on the house floor is to verify that the lines are at right angles to each other. This is very important otherwise the tiles won't come out parallel to every wall. To check the two intersecting centre lines, you can use a steel square of a 3,4,5 set out. The 3,4,5 set out is based on the Pythagorean Theorem where any triangle with the ratio of 3,4,5 for each side has a right angle at the corner opposite the 5 side.
If you find that lines aren't square, you must keep making adjustments until they're. This is because the tiles are set in a grid and squares are important if you want the job to come out right. it's also possible that the walls aren't exactly square but this is the point where you need to find out.
The next step is to start drawing centre lines so that the location of each tile can be marked both ways. it's okay to lay down some individual tiles during this process so that you can give it a quick glance to see how it'll come out. This is sometimes necessary in areas that are complex.
At this point, you've to make some new decisions. You’ll begin to ask yourself questions such as where to make small cuts, where to nudge the tiles over, what to do about the front entry. Any number of problems where the solutions make the difference between perfection and a slight flaw.
Regardless of the decisions you make, you always want to make the first view into your house the best when it comes to tile. After that, you must focus on the appearance of the tile against the wall joints.
It doesn’t hurt and is probably a good idea to get the opinion of another person skilled in tiling to look at what you're planning to do. He may be able to see where adjustments can be made to achieve the optimum look.
Also, because laying tile along walls rarely comes out perfectly. A second opinion can give you some ideas of how to compensate for it. For example, if one wall is out of square, I may apply a wider cut to it so as to keep the tiles parallel to the other walls. I can also make my decisions based on furniture or cupboards that are against that wall.
Use expansion joints when laying tile on a relatively large area. These are discussed below.
The Process
To begin, I make a mark at the centre of the wall and draw the top row of tiles with a pencil. If I see that I'll have a small tile cut at both ends, then I try again. However, the next time, I'll draw the first tile half way on the centre. I'll still use the same number of tiles but get a better look.
it's important to note that by starting the setting out in the middle, I reduce the risk of what's known as discrepancy or creep that tends to accumulate as I continue. This is the reason why I begin by finding the centre of the wall and marking each half of the first tile to the left and right of the centre mark. After that, I make a vertical line that runs along the entire height of the planned tile area. This vertical line will serve as my baseline where I'll begin.
Laying Tiles on New Concrete
You should wait as long as you can for concrete to cure before laying tile on it. Typically you’ll spend four weeks after pouring concrete trying to make it dry slowly by using water. After that, you've to wait for it dry even longer before tile can be laid. Remember that after first pouring concrete, it'll shrink before while it's drying. The first hours of drying go by fairly quickly and then the drying slows.
With the construction of a new house, floor tiles are laid towards the end of the job. It could be as much as 12 weeks following the pouring of the slab. By this point, it’s no problem because the slab has completely cured and the tiles can be laid. Of course the curing time is dependent on the thickness of the slab. However, as a rule of thumb, if the slab is 100mm (4 inches) in thickness then you should wait at least 8 weeks before laying tile. I’ve also heard another rule of thumb that states that you should wait one month for each inch of slab thickness.
According to the BCA, any concrete floor in living spaces that's laid on the ground should've underneath the slab an approved membrane that's waterproof. The reason is to prevent moisture from coming up from the ground and saturating the concrete. If you don’t do this, there is a risk that the tile you laid will separate and keep separating because the concrete isn't fully dry.
Sometimes this happens because a room was built on a slab and the slab wasn't intended to be used for living space initially. If you're unsure of a slab, consult with a knowledgeable person at a tile shop. He might be able to recommend membrane or isolation products that can protect your tile should you be laying it in this type of area.
Setting Out Tile when the Walls are Out of Square
I did a job once where we laid a 6 metre run and when we reached the end, the wall was out of square by 300 in relation to the other walls in the house. We'd to cut the 200 x 200 tiles used on the end in an angle. Up to that point they were square and lined up parallel with the other walls.
The angle was noticeable on the walls, ceiling. Floor. The end result was quite pleasing even though the one wall was out of square. There was really nothing one could do about that.
You can also lay tile diagonally with borders that run parallel with the walls. Remember that it’s the tile pattern that'll reveal these imperfections and your choice to correct it's the diagonal set out.
Something to keep in mind is that it's always easier to measure than it's to cut. So, when you're measuring, you should do it once more just to be sure where you're going to cut your diagonal set outs. The meticulous measuring will reveal imperfections in foundations and walls that may have been unnoticed for years—long after the workers who made them are gone.
Joints
By joints I mean control, movement. Expansion joints. These are used because the materials used in home construction will slip with the passage of time. There are many reasons for this, one of them being because of temperature changes. Ceramic tiles are susceptible to shift as well. To compensate for this, we use expansion joints.
Expansion joints should be placed around the outer edges of the floor. Leave a 5mm gap and don’t let adhesive or grout accumulate at this location between the wall and tile. Most of the time you'll put some skirting over the gap and that'll be it unless the skirting is of the ceramic type. If it's then some flexible sealer such as “Caulk and Colours” will work fine.
If the floor is rather large, a minimum 4mm joint using flexible sealer should be placed about every 5 metres. When there is an existing expansion joint in the concrete floor, you want to put the tile expansion joint over it.
In the event that there is a larger than average crack due to shrinkage in the concrete, you need to put expansion joints under the tiles to keep them from cracking when walking on them. This is done by laying expansion joints on either side of the crack and the laying the tiles over them plus use flexible adhesive underneath.
